Method of producing ring-shaped articles



May 15, 1956 1.. B. GREEN 2,745,122

METHOD OF PRODUCING RING-SHAPED ARTICLES Filed Jan. 11, 1951 '7 Sheets-Sheet l N INVENTOR. 1 EE 5. GREEN 1' E +N M, Q

May 15, 1956 L. B. GREEN METHOD OF PRODUCING RING-SHAPED ARTICLES Filed Jan. 11. 1951 7 Sheets-Sheet 3 w E kw m w W ..u m R gg W w m .v 1 q r vwmmwxx. dNm fl Na FLE W H \MN IM- A May 15, 1956 Filed Jan. 11, 1951 L. B. GREEN 2,745,122

METHOD OF PRODUCING RING-SHAPED ARTICLES 7 Sheets-Sheet 4 May 15, 1956 L. B. GREEN 2,745,122

METHOD OF PRODUCING RING-SHAPED ARTICLES Filed Jan. 11, 1951 7 Sheets-Sheet 6 IN V EN TOR. 4 EE 5. AEEN BYM/i I 9444M W Arro/e/ws Y5 May 15, 1956 L. B. GREEN METHOD OF PRODUCING RING Filed Jan. 11, 1951 SHAPED ARTICLES 7 Sheets-Sheet 7 Illul v VV- Q. MENTOR- 55 5. 6PEEN nited States Patent nutrition on PRODUQHNG RHNG=SHAPED Anricrns Lee R. Green, Lakewoodfihio Application January 11, 1951, Serial-Jo. 295,573

21 Claims. (Cl. -34) This invention relates to the manufacture of pronged fasteners of the ring type adapted to be used between and driven into two wood or other penetrable members to be connected, and relates more particularly to a novel method for producing such pronged ring fasteners rapidly and economically from sheet metal stock. I

An object of the present invention is to provide a novel method for the production of such pronged ring fasteners in which substantially flat pronged fastener blanks are severed in succession from the leading end of a strip of sheet metal stock and are progressively bent to ring shape to form the completed fasteners.

Another object is to provide a novel method for the purpose mentioned in which the pronged fastener blanks severed from the sheet metal strip are maintained in a series relation with the prongs of each blank in .interfitting or meshed engagement with the prongs of an adjacent blank so as to constitute a strip of blanks vand in which the strip of blanks thus produced is curved transversely by wedgingly inwardly and longitudinally acting impact bending forces applied to opposite longitudinal edge portions of the sheet metal strip to convert the blanks into pronged ring fasteners.

A further object is to provide such a novel method in which the strip of pronged fastener blanks is advanced at substantially the rate ofproduction of the blanks and is progressively curved transversely to convert the strip of blanks into a tube from the leading end of which the completed ring fasteners can be disengaged individually or in groups.

Still another object is to provide a novel method of the character mentioned in which the strip of pronged blanks is subjected to a progressive transverse bending in a longitudinally tapered or converging reciprocably movable hollow die member by which the blanks of the strip are curved to the substantially annularly closed ring shape of the completed fasteners.

Yet another object is to provide a novel method for the purpose mentioned in which the bending of the strip of blanks transversely thereof is carried out between cooperating relatively reciprocable coaxial inner and outer die members. i i

This invention also provides such a novel method in which the strip of fastener blanksis advanced intermittently and is held against backward movement during the rest intervals between the intermittent forward movements, and in which the progressive curving of the strip of blanks to the substantially annularly closed shape of the completed fasteners is produced'by impact ibending forces applied to the strip by the hollow die member during such rest intervals.

As another object this invention provides a novel method of the character just mentioned in which the progressive transverse curving'of the strip of blanks is carried out between cooperating coaxial inner andouter die mom bers convergently tapered'in the direction of strip travel and defining a die passage therebetween having a relatively 'ice wide inlet opening adapted to receive the strip of blanks and a substantially annularly closed outlet opening from which the completed pronged ring fasteners are discharged.

Still another object is to provide 'a novel method, of the kind referred to and employing such cooperating inner and outer die members but in which the tapered inner or convex die member is a stationary mandrel about which the strip of blanks is bent by bending forces imparted theret by reciprocation of the outer or concave die member, and in which the tube of fasteners being delivered is supported by a stem extension of the mandrel which projects from the outer die member.

The present invention further provides a novel method for producing pronged ring fasteners in which cooperating toothed or serrated shearing die members sever the successive pronged fastener blanks from the strip of stock and in which certain of the die members have projections thereon which deflect the ends of the prongs outof the plane of the blank'such that when the blank is bent to closed ring shape the deflected ends of the prongs will incline away from the axis of the fastener.

As an additional object, this invention provides a novel method of making pronged ring fasteners in which the major portion of the transverse curving of the strip of lanks is accomplished between the inner mandrel die member and the reciprocably movable hollow outer die member, and in which a further bending of the blanks to a substantially closed ring form is accomplished by a pair of cooperating die rolls connected with the outer die member for translatory movement therewith.

The invention can be further briefly summarized as consisting in certain novel steps of procedure, hereinafter described and particularly set out in the claims hereof.

In the accompanying sheets of drawings,

Fig. 1 is a plan view showing apparatus for the production of pronged fasteners of the ring type in accordance with the novel method of the present invention, the apparatus being viewed in plan substantially as indicated by line 1-1 of Fig. 2;

Fig. 2 is a longitudinal vertical section taken through the apparatus on the irregular section line 2-2 of Fig. 1;

Fig. 3 is a longitudinal vertical section corresponding with the portion of Fig. 2 which illustrates the cooperating punch and stake die members of the shearing die mechanism, but showing such die members on a larger scale and in an open position;

Fig. 4 is a longitudinal vertical section similar to that of Fig. 3 but showing the cooperating punch and stake die members in closed position;

Fig. 5 is a longitudinal vertical section corresponding with the portion of Fig. 2 which illustrates the curving die mechanism for curving the strip of blanks, but showing such curving die mechanism on a larger scale;

Fig. 6 is a partial transverse section showing the receiving end of the curving die mechanism, the view being taken substantially as indicated by line 6-6 of Fig. 5;

Figs. 7, 8 and 9 are transverse sections taken through the purving die mechanism substantially as indicated by sections lines 7-7, 8-45 and 9- respectively, of Fig. 5'

Fig. 10 is a perspective view of the inner die member fastenerv of the kind produced by the method of the present invention;

Fig. 13 is an end view of the completed fastener; Fig. 14 is a plan view of a flat or developed pronged fastener blank showing the same as produced by the shearing die mechanism and prior to being curved to ring shape;

Fig. 15 is a sectional view taken transversely of the fastener blank as indicated by section line 15-45 of Fig. 14;

Fig. 16 is a partial plan view, on an enlarged scale, showing the leading end of the strip of stock and several fastener blanks which have been sheared therefrom and which are in meshed relation forming the rear end of the strip of blanks;

Fig. 17 is a partial horizontal sectional View taken through the shearing die mechanism substantially as indicated by section line 17l7 of Fig. 18;

Figs. 18 and 19 are partial longitudinal sectional views taken through the shearing die mechanism at laterally spaced points, asindicated by sections lines iti--13 and 1919, respectively, of Fig. 17;

Fig. 20 is a partial transverse sectional View taken through the shearing die mechanism substantially as indicated by line 202l0 of Fig. 19;

Fig. 21 is a fragmentary horizontal view of the lower stripper of the shearing die mechanism, the view being taken substantially as indicated by line 2l21 of Fig. 20;

Fig. 22 is an exploded view in perspective showing the component parts of the curving die mechanism; and

Fig. 23 is a plan view showing a modified form of the curving die mechanism.

As representing one form of apparatus suitable for carrying out the novel method, the drawings show a shearing die mechanism by which pronged fastener blanks 11 in a substantially flat or developed form are severed in succsesion from the leading end of a strip of sheet metal stock 12, and a curving die mechanism 13 by which the pronged fastener blanks are curved to a substantially closed annular shape to thereby convert the blanks into pronged ring fasteners 14. The apparatus also includes a feed mechanism for advancing the strip of stock 12 to the shearing die mechanism 10 and -which also supplies the forward motion for advancing the fastener blanks through the curving die mechanism 13. Additionally, the apparatus includes punch press mechanism 1'7 for actuating the shearing die mechanism 10 and lever mechanism 18 for actuating the curving die mechanism 13.

Before proceeding with the more detailed description of the apparatus and method, it is appropriate at this point to describe the pronged ring fastener 14 and the pronged fastener blank 11 from which the completed fastener is formed. As shown in Figs. 12 and 13 the fastener 14 is a ring-shaped sheet metal member having oppositely extending annular groups of substantially triangular prongs 19 and 2b adapted to be driven into two bodies, of wood or other penetrable material, between which the fastener is disposed and which are to be connected by such fastener.

The pronged ring fastener 1 is more fully disclosed and is claimed in copending patent application Serial No. 74,776, filed February 5, 1949, and now patent No. 2,558,132 granted June 26, 1951. As to the manner of using the fastener 14, it is sufficient for the purposes of the present application to explain that when the fastener is disposed between a pair of wood members and the annular groups of prongs 19 and 23 are forced into such wood members these prongs become deflected outwardly or clinched as they imbed themselves in the wood members, thus enabling the fastener to form a rigid and durable connection for holding such wood members firmly together.

As shown in Figs. 12 and 13, the prongs constituting the annular groups of prongs 19 and are disposed in circumferentially offset or staggered relation such that the substantially triangular notches 21 formed between each pair of prongs 19 will be located in axial alignment with the prongs 20 of the opposite group and, similarly, the substantially triangular notches 22 formed between the pairs of adjacent prongs 20 will be located in axial alignment with the prongs 19. The prongs 19 and 20 are of such proportions that they will readily enter the wood members when the fastener is subjected to an appropriate driving force.

To facilitate the outward deflection or clinching of the prongs 29 and 21 as they are forced into the wood members, the free end portions or tops 19a and Ztla are initially deflected outwardly so as to stand in an obtuse angle relation to the axis of the fastener. To enable the fastener 1 2- to draw the wood members tightly together, the notches 2i and 22 are of such depth that their apices will lie on or adjacent a circumferential median line 23.

The completed'pronged ring fasteners 14 are formed from the substantially flat pronged fastener blanks ll which have been sheared in succession from the leading end of the strip of sheet metal stock 12. As shown in Figs. 14, 15 and 16, the fastener blanks 11 have oppositely extending rows of the prongs 19 and 20 thereon with the intervening notches 21 and 22 between the pairs of adjacent prongs. The prong ends 19a and 20a of the prongs 19 and 20 have been deflected downwardly out of the plane of the blank such that when the blank is curved to annular shape these prong ends will stand in the above-mentioned outwardly deflected obtuse angle relation to the axis of the fastener.

It will be seen from Figs. 14 and 16, and from various other views of the drawings, that one of the prong edged fastener blanks 11 is severed from the leading end of the stock strip 12 by each shearing operation. It will also be seen that during each shearing operation, a transversely extending row of the V-shaped notches 21 is cut in the stock strip andthat the V-shaped segments thus sheared out of these notches of the stock strip form the rear row of prongs 20 of the blank. In this novel method, the row of notches 21 being cut by the shearing operation is located at a point on the stock strip which is in such close relation to the previously cut row of these notches remaining on the extreme leading end of the strip, that the oppositely extending V-shaped prongs 19 and 20 will have their bases located substantially on the median line 23 of the blank being produced.

When the fastener blanks 11 are sheared from the leading end of the stock strip 12 they are completely severed from the stock strip but remain in the relation shown in Fig. 16 in which the prongs 20 of the rear edge of one fastener blank are in meshing engagement with the prongs 19 of the forward edge of the next succeeding fastener blank. When the flat fastener blanks ll are. in this inter-engaged or meshed relation they constitute a. so-called strip of blanks 12a to which further reference will be made hereinafter.

As shown in Figs. 3 and 4, the shearing die mecha nism it]! includes a pair of upper and lower carrier plates 25 and 26 of which the lower carrier plate 26 is a stationary member and the upper carrier plate member 25 is reciprocably movable relative to the lower carrier plate. The shearing die mechanism 14) also includes an upper or punch shearing die member 27 and a lower or stake shearing die member 28. Additionally, this shearing die mechanism includes upper and lower stripper die members 29 and 30.

The upper and lower shearing die members 27 and 28 have groups of teeth or serrations 27a and 28a thereon extending toward each other but with the teeth of these groups laterally olfset a distance such that the teeth 27a of the punch 27will be capable of moving downwardly between the teeth 28a of the stake die member 28. The teeth 27a of the punch 27 and the teeth 28:: or" the stake correspond in plan size and shape respectively with the prongs 2i and 119 of the fastener blanks 11. During each such downward movement of the punch 27 in shearing relation to the stake 28, the teeth 27a of the punch will shear the stock strip 12 transversely thereof along a zig-zag line corresponding with the tooth profile of the fastener blank and thereby shear one of the fastener blanks 11 from the leading end of the stock strip.

The punch and stake die members 27 and 28 are here shown as embodying a novel construction in that these die members are composed of groups of blades 31 and 32 disposed in vertically edgewise relation with the blades of each group in face-to-face engagement. The teeth 27a and 28a constituting the shearing elements of these die members are formed by the tapered upright end edges of these grouped blades. When the die members 27 and 28 are composed of such groups of component blades they can be more economically constructed and maintained in a sharp condition because the tapered end edges constituting the shearing teeth can be more readily and accurately formed on individual blades by appropriate machining or grinding operations than they could be on a solid die block.

The blades 31 constituting the punch 27 can be mounted on the carrier plate 25 in the above-described grouped relation by the use of clamping blocks 33 and 34 (see Figs. 3 and 4) between which the blades are disposed and which clamping blocks are connected with the carrier plate by suitable screws 35 and 36. The clamping blocks 33 and 34 have the adjacent faces 33a and 34a thereof disposed in oppositely inclined relation so as to define therebetween a dovetail-shaped space or recess in which the dovetail-shaped upper portions of the blades 31 engage.

The clamping block 34 has limited'shifting movement relative to the clamping block 33 for locking or releasing the blades 31. Such shifting of the clamping block 34 toward the clamping block 33 is produced by actuating screws 38 extending through a backing block 39 which is also mounted on the carrier plate 25. After the clamping block 34 has been shifted by the actuating screws 38 toward the clamping block 33 to grip the dovetail portions of the blades 31 therebetween, the connecting screws 36 are tightened to maintain the clamping block 34 in this relation.

The group of blades 32 of the lower or stake shearing die member 28 are mounted on the lower carrier plate as in a similar manner by the provision of a pair of clamping blocks 49 and 41 and a backing block 42.

The strippers 29 and 30 are upper and lower die members which are in the form of movable blocks located adjacent the clamping blocks 34- and 41 and which cooperate, respectively, with the shearing die members 28 and 27. The upper stripper 29 has a row of teeth or serrations 2% formed on the front edge thereof and which are in meshing engagement with the teeth 27a of the punch 27'. Similarly, the lower stripper 39 is provided with a row of teeth Stla on the upright rear edge thereof which are in meshing engagement with the teeth 4-1 is produced by compression'springs 44 disposed between this stripper and the lower carrier plate 26.

The lower stripper 30 forms a yieldable support for the end portion of the stock strip 12 which overlies the 'teeth 28a of the stake 28, as shown in Fig. 3, and which overlying portion is about to be severed from the stock I strip by the punch 27. When this overlying portion is 28a of the stake 2%. The upper stripper 29 is engageable with the upper surface of the stock strip 12 for applying pressure thereto, as shown in Pig. 4, and the lower stripper 3t) is engageable with the lower surface of the rear end portion of the strip 12a of fastener blanks and with the lower surface of the extreme front end portion of the stock strip l2, as shown in Fig. 3.

The upper stripper 29 is movable toward and away from the clamping block 34 during the closing and opening movements of the punch 27 and the outward or downward movement of this stripper away from the clam ing block 34 is produced by compression springs 43 disposed between this stripper and the carrier plate 25. The lower stripper (it? is movable toward and away from the clamping block 41 during the closing and opening movements of the punch 27 and the outward or upward movement of this stripper away from the clamping block severed from the stock strip it forms a fastener blank 11 which is gripped between the stripper 3t) and the punch 27 and is carried downward by the punch in the complerion of the shearing action performed by the latter. When the punch 27 is moved upwardly by the carrier plate 25 following this shearing operation, the fastener blank 11 just produced is lifted by the lower stripper 3% to a position in meshed alignment with the previously severed fastener blanks.

Another important feature of the shearing die mechanism lit) is that the punch 27 and the upper stripper 29 are provided with rows of depending projections or lugs 46 and 47 which are carried by the teeth 27a and 29a, respectively, and act on the stock strip 12 during the shearing operation to deflect downwardly the end portions 1% 29a of the teeth 19 and 20 of the fastener blank 11 being formed. The lugs 46 and 47 are located at the ends of the teeth 270; and 29a and are formed as integral depending extensions of these teeth. To permit such downward deflection of the ends of the prongs of the fastener blank being formed, the end portions of the teeth 23a and 39a of the stake 28 and the lower stripper 38 are beveled downwardly, as is best shown in Figs. 18 and 19, and these bevels are indicated by the reference characters 48 and 49.

During the closing movement of the die mechanism lltl, the depending lugs 46 and 47 of the punch 27 and the upper stripper 29 engage the upper surfaceof the stock strip 12 ahead of other portions of these die members and the depending lugs 46 start the shearing operation by which the next fastener blank 11 will be sheared from the leading end of the stock strip. The continued downward closing movement of the punch 27 causes the teeth 27a thereof to complete the shearing of the prongs 20 from the stock strip 12. During this shearing operation the lugs 46 cooperate with the beveled portions 49 of the lower stripper 30 to deflect the ends 2tla of the prongs 20 downwardly. Also during'this shearing operation the lugs 47 of the upper stripper 29 cooperate with the beveled portions 48 of the stake 28 to deflect the ends 19a of the prongs 19 downwardly.

The shearing of a fastener blank 11 from the leading end of the stock strip 12 leaves on the stock strip a row of prongs 19 for the next succeeding blank to be sheared from the stock strip. The row of prongs 19 thus formed on the leading end of the stock strip 12 will be completely formed prongs having the downwardly deflected ends 19a such that when the next fastener blank 11 is sheared from such leading end of the stock strip it will only be necessary for the shearing operation to form the prongs 20 and the downwardly deflected ends 20a. Thus each closing of the die mechanism 10 will result in a completely formed fastener blank 11 being severed from the stock strip 12.

During the opening movement of the die mechanism Hi the upper carrier plate 25 is moved upwardly away from the stationary lower carrier plate 26 and, during the initial portion of this opening movement, the springs 43 maintain the upper stripper 29 stationary for a short interval of time thereby holding the stock strip 12 clamped against the stake 23 until the groups of shearing teeth 27a and 28a of the die members 27 and 28 have separated from each other. During such opening movement of the die mechanism 10, the lower stripper 30 is lifted by the springs 44, thereby elevating the last-severed fastener blank ill, and also several previously severed adjacent blanks, to a position of axial alignment with the strip 12a of fastener blanks, as shown in Fig. 3.

The opening and closing actuation of the shearing die mechanism lid is accomplished by suitable actuating mechanism which is here shown as being a conventional punch press 17 (see Figs. 1 and 2) having a bed 51 and a reciprocable ram or slide 52. The upper carrier plate is suitably attached to the lower end of the ram 52 and the lower carrier plate 26 is suitably mounted on a table 53 which is in turn carried by a bolster plate mounted on the bed 51. As is customary in punch presses, the

' ram 52 is actuated in a conventional manner from a crankshaft (not shown) such as to produce the desired recipro eating opening and closing movements of the upper carrier plate 25 relative to the lower carrier plate 25.

The feed mechanism advances the stock strip 12 to the die mechanism fill with an intermittent forward movement in timed relation to the opening and closing movements of this die mechanism. This feed mechanism is here shown as comprising a pair of cooperating upper and lower feed rolls 55 and 56 which are adapted to grip the stock strip 12. One or both of the feed rolls and 56 are adapted to be driven by linkage actuated from the crankshaft of the punch press 17.

in this instance the actuating linkage for the feed rolls is shown as comprising a lever 57 which is drivingly connected with the lower feed roll 56 by means of a ratchet wheel 58 and a pivoted pawl 59. The lever 57 is rock- I able about the axis of the lower roll 56 and carries the pawl 59. A thrust link 69 connects the lever 57 with the crankshaft of the punch press. Swinging movements imparted to the lever 57 cause the lower feed roll to be driven with an intermittent forward feeding movement by the ratchet wheel 58 and the pawl 59 to thereby advance the stock strip 12 to the shearing die mechanism 16 with a step-by-step movement.

The stock strip 12 may be supplied from available source of supply such as a roll of this strip material from which the strip is withdrawn by the feed rolls 55 and 56 of the feed mechanism 15. in. passing from the feed rolls to the shearing die mechanism 10, the strip 12 is supported on a feed plate 61 and is confined in a longitudinal guideway 62 by the overlapping edge portions 63a of a pair of laterally spaced strips 63. The strip 12a formed by the intermeshed fastener blanks ill passes to the curving die mechanism 13 by moving through a clamping device 65. This clamping device serves to hold the strip of blanks against backward movement during the operation of the curving die mechanism T13 and is constructed and operated as a part of the shearing die mechanism lit.

The clamping device 65 comprises a pair of upper and lower clamping members 66 and 67 and a pressure plate 68. These clamping members 66 and 67 define therebetween a longitudinal guide passage 6% which is aligned with the guideway 62 and direct the strip 12a of fastener blanks to the curving die mechanism 13. The lower clamping member 67 is located immediately adjacent the backing block 42 and is secured to the lower carrier plate 26.

The upper clamping member 66 is connected with the lower clamping member 67 by screws 76 which permit a limited movement of this upper clamping member toward and away from the lower clamping member for clamping or releasing the strip 12a of fastener blanks. Compression springs 71 disposed between the clamping members 66 and 67 act on the upper clamping member to normally urge the same away from the lower clamping member so as to release the clamping pressure on the strip of blanks. As shown in Figs. 3 and 4 the upper clamping member 66 is provided with an integral lateral extension 66a which projects rearwardly in overlying re lation to the backing block 42 and a portion of the lower stripper 30.

The pressure plate 68 is connected with the upper carrier plate by screws 72 which permit relative movement between the pressure plate and this carrier plate. Compression springs 73 disposed between the upper carrier plate and the pressure plate 68 act on the latter to normally urge the same in a downward direction away from the carrier plate.

Nhen'the die mechanism llll is being closed by downward movement of the carrier plate 25, the pressure plate 63 engages the upper clamping member 66 before the punch 27 or the upper stripper 29 engages the stock strip 12 and applies downward pressure to this upper clamping member, causing the same to compress the springs 'Yl and clamp the strip 12a of blanks against the lowerclamping member 67. Such downward movement of the upper clamping member 66 also'causes the extension portion 66a thereof to cooperate with the backing block 42 and the stripper 30 to apply clamping pressure to the portions of the strip 32a which are located in overlying relation to this backing block and stripper.

While this clamping pressure is maintained on the strip 12a of fastener blanks by the upper clamping member 66 this strip is held against backward movement so as to enable the curving die mechanism 13 to carry out its curving function, as explained hereinafter. The holding of the strip of blanks against backward movement by the upper clamping member 66 also prevents jamming of the dies 27 and 28 during the shearing operation such as might otherwise occur if movement or pressure were transmitted in a backward direction through the previously sheared fastener blanks to these shearing dies or to the leading end of the stock strip 3 .71.

The bottom of the guide passage 69 of the clamping device is formed by the top surfaces of the lower clamping member 67, the backing block 42 and the stripper Sit and during the advance movement of the strip 12a of blanks the individual blanks ill slide on these top surfaces. To prevent the downwardly deflected prong ends 19:: and 20a of the fastener blanks from becoming flattened or dulled by the clamping pressure being applied by the clamping device 65, a plurality of longitudinal grooves '75 of substantially triangular cross-section are formed in the top surface of the stripper 30, the backing block 42 and the clamping member 67. These grooves accommodate the downwardly deflected ends of the prongs l9 and 26 of the fastener blanks while the blanks are in the passage 69.

As shown in Figs. 20 and 21, the grooves '75 are disposed in a laterally spaced relation corresponding with the lateral spacing ofthe prongs l9 and 20 of the fastener blanks H. The grooves 75 of the stripper 30, the backing block 42 and the lower clamping member 67 are in an aligned relation so as to form continuous channels in which the downwardly deflected prong ends are longitudinally movable during the advance travel of the strip of blanks.

The curving die mechanism 13 and its function constitute an important part of this invention and will be described neXt. As shown in Figs. 2 and 5, the curving die mechanism 13 is mounted on the table 53 to the right of and immediately adjacent the shearing die mechanism it) so as to receive the strip 124: of fastener blanks from the latter. The curving die mechanism comprises, in general, a longitudinal guidebox 77 and a pair of coaxially extending inner and outer curving dies 78 and 79 disposed in such guideboX.

The guidebox 77 comprises a channel-shaped bottom member 7751 and a cover 77]). The channel-shaped bottom member 77a has laterally spaced upright side walls 84) connected by a transverse bottom wall 81 such that these walls define a longitudinal guideway The side and bottom walls are preferably provided with a lining of suitable bearing material 83. The bottom member 7'71: is secured to the table 53 as by means of the screws 34 which extend into integral depending legs 85 provided at the ends of this bottom member and which are held against the table by the attaching screws.

The cover 771) is secured to the side walls of the bottom member '77:: in covering relation to the guideway 82,

as by suitable screws 86. The cover is also provided on the underside thereof with strips 87 of suitable bearing material. The cover 77b al 10 forms a support for the inner die member 78 and, for this purpose, is provided with longitudinally spaced depending abutment lugs 88a, 88b and 880 against which the inner die member is held by clamping screws 89.

The inner die member 78 is in the form of a longitudinally extending convexly curved mandrel which varies progressively in shape from a relatively wide fiat portion 78a at the receiving end of the curving die mechanism 13 to a substantially circular rod portion 7812 at the delivery end of the curving die mechanism. The longitudinal side edges 90 of the flat portion of this inner die are rounded to a radius of curvature corresponding substantially with the radius of curvature of the rod portion 78b such that the longitudinally converging taper of these rounded side edges will merge smoothly into the rod portion 78b.

The inner die or mandrel 75 preferably has transverse recesses 91 formed in the top surface thereof and spaced apart longitudinally to correspond with the spacing of the abutment lugs 38 of the cover 77b. When the die 78 is connected with the cover by the screws 89, the abutment lugs 88 engage in the recesses 91 such that the abutment lugs hold the die firmly in place in the guidebox 77 and absorb the longitudinal thrust to which this die is subjected during the curving operation.

The strip 12a of fastener blanks is delivered into the guidebox 77 beneath the wide flat end 780 of the inner die 78, as shown in Figs. and 6. For supporting the strip 12a in the guidebox such that this strip will lie against the bottom surface of the inner die 78, the guidebox is provided with a strip support 92 which is here shown as being a substantially wedge-shape plate member. The strip support 92 extends longitudinally in the guidebox 77 between the laterally spaced portions 83a of the bearing material carried by the bottom wall 81 and is secured to such bottom wall by suitable screws 92a.

The outer die member 79 of the curving die mechanism 13 is a hollow die member which is concavely curved internally thereof and embraces the inner die member or mandrel 78. As shown in the drawings, this outer die member 79 comprises a pair of elongated die blocks 79a and 7% having complemental longitudinal grooves 94 and 95 in their adjacent faces. At their forward ends the die blocks 7% and 79b have substantially straight portions 93 and the complemental grooves 94 and 95 of these straight portions define a substantially cylindrical passage portion 199]) through which thestem or rod portion 7 8b of the inner die 78 extends.

The die 79 is of such length in relation to the'die box 77 that the straight forward ends 93 of the die blocks 79a and 7% project from the forward end of the die box. Rearwardly of the straight portions 93, the die blocks 79a and 79b are of a tapered form with respect to their adjacent faces such that the grooves 94 and 95 thereof extend in a laterally spaced rearwardly diverging relation and embrace the rounded longitudinal side edges 90 of the tapered portion of the inner die 78.

The die blocks 79a and 7% are held in connected rela tion at their forward ends by a pair of upper and lower splice plates 96 and 97 which are secured to the straight portions 93 by screws 98. The rearwardly extending tapered portions of the die blocks 79a and 79b have tapered spacing blocks 100a, 1019b and 100a located therebetween above the grooves 94 and 95 and are held in connected relation by screws 101 which extend through these spacer blocks. The adjacent ends of the spacer blocks 100a and ltltlb define a gap ltllthrough which the depending abutment lug 38b of the cover 77b extends and the adjacent ends of the spacer blocks and 1000 define another such gap 103 through which the depending abutment lug 880 of the cover extends.

It will be understood that the spacer blocks 100a, 1130b and 1000 are located between the opposed pair of longitudinal clamping faces 104 and 105 of the die blocks 79a and-79b and that when the die blocks are secured together bythe screws 191 the die blocks and spacers form a rigid assembly constituting the outer die member 79. The lower pair of opposed longitudinal faces 106 and 197 of the die block 7941 and '79b lie on opposite sides of the strip support 92 as shown in Figs. 6 and 7.

When the inner die or mandrel 78 and the hollow outer die 79 are assembled in the guidebox 77 they occupy the relative positions shown in Figs. 5, 6 and 7, such that the inner and outer die members define therebetween a longitudinal die passage 109 which varies progressively in shape longitudinally of the curving die mechanism from a passage portion 10% having a relatively wide flat bottom at its receiving end (Fig. 6) to a substantially cylindrical passage portion 10911 at its discharge end (Figs. 8 and 9). This die passage is traversed by the strip 12a of fastener blanks and during the forward travel of the strip through this passage, its cross-sectional shape is changed progressively, as shown in Figs. 10 and 11, from a flat strip into a substantially cylindrical tube 110 of completed ring-shaped fasteners 14.

During this progressive change in the shape of the tions of the strip are deflected upwardly and inwardly by the concavely curved sides of the die passage 199 so as to conform to the transverse curvature and longitudinal taper of the inner die 78. The upward and inward curving of the longitudinal edges of the strip 12a causes this strip to be progressively wrapped around the inner die and results in these edges ultimately being brought into an opposed or substantially abutting relation, as indicated by the longitudinal line 111 of Fig. 11.

In accomplishing the upward and inward curving of the longitudinal edges of the strip 12a, the outer die 79 is reciprocated in the guidebox 77 such that during each working stroke of this outer die it moves rearwardly around and in closing relation to the tapered portion of the innerdie 78, causing the divergently tapered transversely curved walls of the grooves 94 and to impinge the longitudinal edges of the strip and bend the same around and against the curved longitudinal edges of the inner die. These working strokes need be of only a relatively short travel, inasmuch as a short longitudinal movement of the outer die in a rearward direction will cause a rapid closing of the diverging grooves 94 and 95 relative to the longitudinal side edges of the tapered flat portion of the inner die 78.

The impingement of the longitudinally divergent transversely curved walls of the hollow outer die 79 against the opposite edge portions of the strip 12a by the successive rearward strokes of this die, results in wedging impact bending forces being repeatedly applied to such edge portions externally of the tubular shape into which the strip is being converted. These impact bending forces are therefore substantially opposed wedgingly inwardly and longitudinally acting impact bending forces which are very effective in causing the progressive curving of the strip to tube form while it is being advanced through the curving die mechanism 13.

The working strokes which produce the closing movement of the outer die 79 relative to the inner die 78 are carried out in such timed relation to the functioning of the shearing die mechanism 10 and the clamping device 65 that during the bending of the longitudinal edges of the strip 12a around the inner die the strip will be sta- .tionary and will be held against backward movement by the clamping device. During the return or opening movement of the outer die 79 relative to the inner die 78 and during such time that the outer die is in its open position, the strip 12a is free to be advanced by increments of forward movement applied to the rear end of this strip by the leading end of the stock strip 12.

For accomplishing the final portion of the curving of the strip 12a of blanks into the tube 110, the outer die- 79 is preferably provided with a pair of cooperating rolls 112 and 113 which are located respectively in recesses of the straight end portions 93 of the die blocks 7 9a and 79b. The rolls 1 12 and 113 have annular grooves 114 therein corresponding in curvature with the tubular delivery portion ltWb of the die passage such that when the forward end of the strip 12a traverses this delivery portion, these rolls will squeeze and size the tube 110 so as to bring the edges thereof into substantially meeting relation along the line 1111. and such that the completed fasteners 14- will all be of a substantially uniform diameter. The rolls 112 and 113 are rotatably mounted in the splice plates 96 and 97 and, for this purpose, are provided with shaft extensions 112a and 113:; which are journaled in suitable bushings 115 carried by these splice plates.

As shown in the drawings, the rod portion 78b of the inner die 78 is of a length to extend through and project from the tubular delivery portion 1 3% of the die passage and the forwardly projecting portion of this red constitutes a support for the tube 110 of completed pronged ring fasteners 14. Since the blanks from which these fasteners have been shaped are completely severed from each other, it will be seen that the fasteners are maintained in the tubular relation merely by the interengagement or meshing of the prongs of adjacent fasteners. The completed fasteners can therefore be readily disengaged from the leading end of the tube 110, either as individual fasteners or as stacks of such fasteners. The completed fasteners 14 which have been thus disengaged from the leading end of the tube 11f can be suitably packaged for sale either in a bulk condition or as stacks of fasteners for use in the magiznes of various fabricating machines.

Various forms of actuating mechanism can be employed for imparting the reciprocating working and return strokes to the outer die member 79 of the curving die mechanism 13. in this instance actuating mechanism 18 is provided which includes a transverse rockshaft 117 located adjacent the right-hand end of the table 53 and to which rocking movements are imparted by a lever 118. The rockshaft 117 is journaled in a pair of laterally spaced arms i119 and 12d of a bearing bracket 121 which is secured to the table 53 as by means of the screws 122.

A forked lever 123 mounted on and keyed to the rockshaft H7 between the arms 119 and 120 of the bearing bracket 121 has a pair of upwardly projecting laterally spaced lever arms 123a and 123]). Pivot pins illcarried by the upper ends of the lever arms 123a and 12312 project outwardly therefrom in laterally aligned relation. A pair of links 125 and 126 connect the arms 123a and 1231) with the forward end of the outer die 79. For this purpose the thrust links 1125 and 126 are pivoted at one end thereof on the pivot pins 124- and at the opposite end thereof are connected with the outer die 79 by means of a pair of pivot pins 127. The pivot pins 1'27 are here shown as being in the form of studs mounted in the straight end portions 93, the die blocks 79:: and 79b and projecting laterally outwardly therefrom in substantially aligned relation.

The actuating mechanism 35 also includes a link 1128 connecting the lever 118 of the rockshaft 117 with a bcllcrank lever i239. The lever 129 is carried by a shaft 138 which is journaled in a bearing bracket 131 mounted on the cover 7715 of the guidebox '77. The bellcrank lever 129 comprises lever arms 129a and 1291;, of which the lever arm 129a is pivotally connected with the link 128. The lever arm 12911 carries a roller 152 which engages in the recess T33 of a brackct 13 3 which is carried by and reciprocably movable with the ram 52 of the punch press 17. When the die member 79 of the curving die mechanism 13 is actuated by movement transmitted from the ram 52 of the punch press 17 through an arrangement of levers and links such as that just described above, it will be seen that the strokes of the die member 79 will be produced in a 12 desired timed relation to the actuation of the shearing die mechanism and the clamping device 65, as well as in timed relation to the intermittent forward movement provided by the feed device 15 for the stock strip 12 and the strip 12a of fastener blanks.

Before summarizing the detailed operation of the apparatus and novel method of this invention, it should be explained that the sheet metal of the stock strip 12 can be of any desired thickness or gauge, depending upon the nominal size and requirements of the pronged ring fasteners 14 being produced. The longitudinal taper of the inner and outer dies 73 and '79 of the curving die mechanism 13 bears an important relation to the thickness of the sheet metal of the stock strip 12 and to the angularity or extent of deflection of the prong ends 1% and Ztla, in that the taper angle of these die members should be of such gradual slope that the prongs of the adjacent fastener blanks 11 of the strip 12:! will remain in the above expained inter-engaged or meshed relation during the curving of the strip into the tube 11110. It is important that the prongs of the adjacent fastener blanks 11 of the strip 12a remain in such meshed relation because the advanced movement of all of the fastener blanks through the curving die mechanism 13 can then be produced by motion supplied to the rear end of the strip 12a by the leading end of the stock strip 12.

The production of the pronged ring fasteners 14 by the apparatus and novel method of this invention has already been explained to a considerable extent in the foregoing detailed description, such that only a summarization of the detailed operation will need be given at this point. The strip 12 of sheet metal stock is advanced with a step-by-step feeding movement by the feed roll mechanism 15. Fig. 3 shows the leading end of the strip stock 12 in a position overlying the stake die member 28 and the lower stripper 3i) and in readiness for the shearing of the next fastener blank 11 therefrom by the punch 27 and the stripper 2?. Fig. 4 shows the die members of the shearing die mechanism It} in their closed position in which the next fastener blank referred to above has just been sheared from the leading end of the stock strip 12.

During the closing of the die mechanism 10, the gripping device 65 is actuated to apply a clamping force to a small number of the fastener blanks constituting the rear end of the strip 12a. This clamping of the rear end of the strip of blanks in the clamping device 65 holds the strip of blanks against backward movement and prevents the fastener blanks which have just been sheared from the stock strip 12 from being pushed against the leading end of the stock strip such as might cause jamming of the shearing die mechanism during the shearing of the next fastener blank from the stock strip.

While the rear end of the strip 12a of fastener blanks is being clampingly held against backward movement by the clamping device 65, the ram 52 of the punch press 17 continues its downward movement to carry out the shearing of the fastener blank from the stock strip 12. This continued downward movement of the ram 52 causes a counter-clockwise rocking movement to be imparted to the bellcrank lever 129 by the bracket 134. This rocking movement of the bellcrank lever 129 applies a pulling force through the link 128 which swings the lever 118 toward the left, thereby causing the thrust links I25 and 126 to transmit actuating movement to the outer die 79 of the curving die mechanism 13.

The resulting movement of the outer die 79 toward the left causes the concavely curved internal wall portions of this die member which define the die passage M9 to impinge against the longitudinal side edges of the strip 312a and curve such side edges upwardly and inwardly around the inner die 73. The working strokes of the ram 52 can be carried out very rapidly and, with each closing of the die mechanism 11) to produce another one of the fastener blan'is 11, the outer die 79 of the curving die mechanism 13'will be moved through a working stroke to impart a bending force to the longitudinal side edges of the strip 12a.

During the opening of the die mechanism 10, the ram 52 moves upwardly thereby rocking the bellcrank lever 129 in a clockwise direction and transmitting motion to the outer die '7) in a direction to retract or open the same relative to the inner die 78. The upward movement of the ram 52 also releases the clamping force being applied to the rear end of the strip of blanks by the clamping device 65, after which the feed mechanism 15 is actuated by the link 6% to impart another forward feeding movement to the stock strip 12. During such forward feeding movement of the stock strip 12, its forward end pushes the strip 12a of fastener blanks in a forward direction, thereby advancing this strip a similar distance into the curving die mechanism 13.

As the result of the step-by-step forward feeding movement of the strip 12a of fastener blanks through the curving die mechanism 13 and the progressive curving of this strip of blanks into the tube 110, the completed ring fasteners 14 will emerge from the forward end of the outer die '79, as shown in Figs. 1 and 5. The tube of completed ring fasteners will move along and be supported by the rod extension 78b of the inner die 78 from which the completed ring fasteners can be removed individually or in groups or" stick form, as may be desired.

Fig. 23 of the drawings shows a modified form of apparatus for carrying out the method in producing the pronged ring fasteners 14 in two parallel groups. In this improved apparatus a curving die mechanism 136 is shown having a pair of outer die members 137 and 138 which are reciprocable in a side-by-side relation in a guidebox 139. This curving die mechanism is also provided with two axially extending inner die members or mandrels 140 and 141 disposed in the guidebox 139 and with which the outer die members 137 and 138 cooperate in the same manner and for the same purpose as the outer die 79 and the mandrel 78 of the curving die mechanism 13 described above.

The reciprocable outer die members 137 and 138 cooperate with their respective mandrels 140 and 141 in defining progressively converging die passages through which two strips of fastener blanks 142 and 143 are advanced in the same manner as described above for the strip of blanks 12a. The discharge ends of these die passages are defined by substantially cylindrical die tubes 144 and 145 mounted in the outer die members 137 and 138 and disposed in surrounding relation to stem extensions of the mandrels 141i and 141.

Reciprocating movement is imparted to the outer die members 137 and 138 by mechanism similar to the above described mechanism 18 and which includes a rockshaft 148 and levers 149 and 150 carried by the rockshaftand connected with the die members 137 and 138 by thrust links 151 and 152. The die members 137 and 138 are connected into a unitary assembly by connecting means which includes .a pair of upper and lower splice plates 153 applied to the forward end portions of these die members. i

The strips of blanks 142 and 143 are supplied to the curving die mechanism 136 by a shearing die mechanism 11 similar to that already described above. The two strips of blanks 142 and 143 are produced by the shearing die mechanism 111 by operation thereof on two parallel stock strips which are supplied thereto by a feed mechanism similar to the feed mechanism 15 above described. The two stock strips thus supplied can be individual strips withdrawn from separate rolls of stock material or can be a single wide strip of sheet metal stock which is split 14 longitudinally by a suitable slitting device, such as a rotatable shearing disk cooperating with a backing roll (not shown), by which the single wide strip is split into two parallel individual stock strips during the feeding movement supplied by the feed mechanism 15.

Withrespect to the die tubes 144 and of the curving die mechanism 136, it should be explained that these die tubes accomplish a shaping and sizing of the transversely curved strips 142 and 143 into tubes of completed fastener blanks similar to the function performed by the cooperating rolls 112 and 113 of the curving die mechanism 13. If desired, rolls similar to the rolls 112 and 113 could be used in the modified curving die mechanism 136 in place of the die tubes 144 and 145 and, conversely, a die tube similar to one of the die tubes 144 and 145 could be used in the curving die mechanism 13 in place of the cooperating rolls 112 and 113.

From the accompanying drawings and the foregoing detailed description it will now be readily understood that this invention provides a novel method by which pronged ring fasteners can be produced rapidly and economically and of a desired uniform characteristic from sheet metal in strip form. I

Although the novel method of the present invention and apparatus for carrying out the method have been illustrated and described herein to a somewhat detailed extent it will be understood, of course, that the invention is not to be regarded as being limited correspondingly in scope but includes all changes and modifications coming within the terms of the claims hereof.

Having thus described my invention, I claim:

1. The method of making pronged annular fasteners which comprises, imparting a forward feeding movement to a strip of sheet metal stock, severing sections in succession from the leading end of said strip transversely thereof .to form fastener blanks of a length corresponding substantially with the developed length of the annular fastener being produced, forming prongs on said blanks, maintaining said blanks in a series relation so as to constitute a strip of blanks, curling said strip of blanks transversely thereof to substantially tubular form by repeatedly imparting wedgingly inwardly and longitudinally acting impact bending forces to opposite edge portions of said strip of blanks, and separating completed pronged annular fasteners from the curled strip.

2. The method of making pronged annular fasteners which comprises, imparting a forward feeding movement to a strip of sheet metal stock, severing sections in succession from the leading end of said strip transversely thereof to form fastener blanks of a length corresponding substantially with the developed length of the annular fastener being produced and in the same operation forming prongs on said blanks, maintaining said blanks in a series relation so as to constitute a strip of blanks, curling said strip of blanks transversely thereof to substantially tubular form by intermittently advancing said strip of blanks through a tapered die passage of a longitudinally movable die such that the strip of blanks has rest intervals between the successive forward movements thereof and meanwhile imparting longitudinal reciprocating movement to the die and impinging the die against said strip of blanks during said rest intervals, and separating completed pronged annular fasteners from the curled strip.

3. The method of making pronged annular fasteners which comprises, imparting a forward feeding movement to a strip of sheet metal stock, severing sections in succession from the leading end of said strip transversely thereof to form fastener blanks of a length corresponding substantially with the developed length of the annular fastener being produced, forming prongs on said blanks along both side edges thereof, maintaining said blanks in a series relation so as to constitute a strip of blanks and with the prongs of one blank in interfitting engagement with the prongs of an adjacent blank, curling said strip of blanks transversely thereof to substantially tubular form by repeatedly imparting wedgingly inwardly and longitudinally acting impact bending forces to opposite edge portions of said strip of blanks by advancing said strip of blanks through a tapered die passage of a longitudinally movable die and meanwhile imparting longitudinal reciprocating movement to the die, and separating completed pronged annular fasteners from the curled strip.

4. The method of making pronged annular fasteners which comprises, imparting a forward feeding movement to a strip of sheet metal stock, severing sections in succession from the leading end of said strip transversely thereof to form fastener blanks of a length corresponding substantially with the developed length of the annular fastener being produced and in the same operation forming prongs on said blanks along both side edges thereof, maintaining said blanks in a series relation so as to constitute a strip of blanks and with the prongs of one blank in interfitting engagement with the prongs of an adjacent blank, curling said strip of blanks transversely thereof to substantially tubular form by advancing the strip of blanks between axially coextending longitudinally tapered hollow die and mandrel die members and meanwhile reciprocating one of said die members and thereby repeatedly causing relative axial closing movement between the die members and a resultant longitudinally wedghigly acting impingement of said one die member against said strip of blanks while the latter is backed by the other die member, and separating completed pronged annular fasteners from the curled strip.

5. In a method of making pronged ring fasteners of the kind having substantially axially extending prongs on opposite ends thereof the steps of, imparting a forward feeding movement to a strip of sheet metal stock, repeatedly shearing said strip transversely thereof adjacent its leading end and on an irregular line corresponding with the prong profile to form completely severed pronged fastener blanks of a length corresponding substantially with the developed length of the ring fastener being produced but with the prongs of adjacent blanks remaining in interfitting engament such that the blanks constitute a strip of blanks, curling said strip of blanks transversely thereof to partial tube form by repeatedly imparting wedgingly inwardly and longitudinally acting impact bending forces to opposite longitudinal edge portions of said strip of blanks, and further curling said strip to blanks to substantially closed tube form by applying transversely acting rolling pressure to opposite sides of the partially formed tube.

6. In a method of making pronged ring fasteners of the kind having substantially axially extending prongs on opposite ends thereof the steps of, imparting a forward feeding movement to a strip of sheet metal stock, repeatedly shearing said strip transversely thereof adjacent its leading end and on an irregular line corresponding with the prong profile to form completely severed pronged fastener blanks of a length corresponding substantially with the developed length of the ring fastener being produced but with the prongs of adjacent blanks remaining in interfitting engagement such that the blanks constitute a strip of blanks, curling said strip of blanks transversely thereof into a tube at substantially the rate of production of said blanks by leading the strip of blanks with an intermittent forward movement through a transversely curved forwardly converging tapered die passage of a longitudinally movable die member such that the strip of blanks has rest intervals between its successive forward movements and repeatedly moving said die member rearwardly to impinge against and apply wedgingly inwardly and longitudinally acting bending forces to opposite edge portions of said strip of blanks during said rest intervals of the latter, and disengaging completed pronged ring fasteners from the end of said tube.

7. In a method of making pronged ring fasteners of the kind having substantially axially extending prongs on opposite ends thereof the steps of, imparting a forward 16 feeding movement to a strip of sheet metal stock, repeatedly shearing said strip transversely thereof adjacent its leading end and on an irregular line corresponding with the prong profile to form completely severed pronged fastener blanks of a length corresponding substantially with the developed length of the ring fastener being produced but with the prongs of adjacent blanks remaining in interfitting engagement such that the blanks constitute a strip of blanks, curling said strip of blanks transversely thereof into a tube by repeatedly impinging opposite sides of a transversely curved longitudinally tapered die passage of a reciprocably movable hollow die against opposite longitudinal side portions of said strip of blanks, advancing said strip of blanks and said tube at substantially the rate of production of said blanks by a pushing feeding movement supplied by said strip of stock and with intermittent forward movements of the strip of blanks occurring between the successive impingements of said hollow die against said strip of blanks, and disengaging pronged ring fasteners from the leading end of said tube.

8. In a method of making pronged ring fasteners of the kind having substantially axially extending prongs on opposite ends thereof the steps of, imparting a forward feeding movement to a strip of sheet metal stock, repeatedly shearing said strip transversely thereof adjacent its leading end and on an irregular line corresponding with the prong profile to form completely severed pronged fastener blanks of a length corresponding substantially with the developed length of the ring fastener being produced but with the prongs of adjacent blanks remaining in interfitting engagement such that the blanks constitute a strip of blanks, curling said strip transversely thereof to partial tube form by intermittently advancing the strip of blanks between coextending longitudinally tapered hollow die and mandrel die members and meanwhile reciprocating one of said die members and thereby causing relative axial closing movement between the die members and a resultant longitudinally wedgingly acting impingement of said one die member against said strip of blanks while the latter is stationary and backed by the other die member, further curling said strip by rolling to substantially closed tube form, and separating the completed pronged ring fasteners from the end of the tube.

9. In a method of making pronged ring fasteners of the kind having substantially axially extending prongs on opposite ends thereof the steps of, imparting an intermittent forward feeding movement to a strip of sheet metal stock, repeatedly shearing said stock strip transversely thereof at a point adjacent its leading end and on an irregular line corresponding with the prong profile to form a series of pronged fastener blanks of a length corresponding substantially with the developed length of the ring fastener being produced and in which the prongs of adjacent blanks are in interfitting engagement such that said series constitutes a strip of said blanks, imparting an intermittent forward movement to said strip of blanks, preventing backward movement of said strip of blanks during the rest intervals of the intermittent forward movement thereof, and deflecting longitudinal edge portions of said strip of blanks inwardly into substantially opposed relation by imparting wedgingly inwardly and longitudinally acting bending forces to opposite edge portions of said strip of blanks during said rest intervals to convert said blanks into substantially completed ring fasteners.

10. A method of making pronged ring fasteners as defined in claim 9 in which the intermittent forward movement of said strip of blanks is produced by thrust applied to the rear end of said strip of blanks so as to maintain the prongs of adjacent blanks in said interfitting engagement.

ll. A method of making pronged ring fasteners as defined in claim 9 in which the intermittent forward movement of said strip of blanks is produced by thrust delivered by the leading end of said stock strip and applied 1'? thereby to the rear end of said strip of blanks so as to maintain the prongs of adjacent blanks in said interfitting engagement.

12. In a method of making pronged ring fasteners of the kind having substantially axially extending prongs on opposite ends thereof the steps of, advancing a relatively wide sheet metal web, splitting said web into a plurality of stock strips of a width corresponding substantially with the developed length of the ring fastener being produced, repeatedly shearing said stock strips transversely thereof adjacent their leading ends and on an irregular line corresponding with the prong profile to convert said stock strips into strips of pronged blanks in which the blanks are completely severed from each other and from the stock strips but adjacent blanks 'of the same blank strip have their prongs in interfitting engagement, and shaping the blank strips to a substantially annularly closed tube shape to convert the pronged blanks to ring form by repeatedly imparting wedgingly inwardly and longitudinally acting impact bending forces to opposite edge portions of said blank strips.

13. In a method of making prolonged ring fasteners of the kind having substantially axially extending prongs on opposite ends thereof the steps of, advancing a strip of sheet metal stock of a width substantially equal to the developed length of the fastener being produced, repeatedly shearing the stock strip transversely thereof adjacent its leading end and on an irregular line corresponding with the prong profile so as to sever from the strip by each such shearing operation a fastener blank having rows of prongs extending along opposite sides thereof, deflecting the ends of said prongs out of the plane of said blank so that the prong ends all lie on one side of said plane, maintaining the blanks in a series relation to constitute a strip of blanks and with the prongs of one blank in interfitting engagement with the prongs of an adjacent blank, advancing said strip of blanks, and curving said strip of blanks transversely thereof to substantially tubular form by bending longitudinal edge portions of said strip of blanks in a direction away from said one side of said plane, said curving being accomplished by repeatedly imparting wedgingly inwardly and longitudinally acting impact bending forces to opposite edge portions of said strip of blanks.

14. In a method of making pronged ring fasteners of the kind having substantially axially extending prongs on opposite ends thereof the steps of, advancing a strip of sheet metal stock of a width substantially equal to the developed length of the fastener being produced, repeatedly shearing thestock strip transversely thereof adjacent its leading end and on an irregular line corresponding With the prong profile so as to sever from the strip by each such shearing operation a fastener blank having rows of prongs extending along opposite sides thereof and during each such shearing operation defiecting the ends of the prongs of both rows of the blank being severed out of the plane of such blank so that the prong ends all lie on one side of said plane, maintaining the blanks in a series relation to constitute a strip of blanks and with the prongs of one blank in interfitting engagement with the prongs of an adjacent blank, and curving said strip of blanks transversely thereof to substantially tubular form by bending longitudinal edge portions of said strip of blanks in a direction away from said one side of said plane, said curving being accomplished by intermittently advancing the strip of blanks between axially coextending longitudinally tapered hollow die and mandrel die members and meanwhile reciprocating one of said die members and thereby causing relative axial closing movement between the die members and a resultant longitudinally wedgingly acting impingement of said one die member against said strip of blanks while the latter is stationary and backed by the other die member.

15. In a method of making pronged ring fasteners of the kind having substantially axially extending prongs on opposite ends'thereof the steps of, advancing a strip of sheet metal stock, repeatedly shearing the stock strip transversely thereof adjacent its leading end and on an irregular line corresponding with the prong profile to convert said stock strip into a strip of fastener blanks having a length corresponding with the developed length of the fastener being produced and also having rows of prongs extending along opposite sides thereof and in which the prongs of adjacent blanks are in interfitting engagement, deflecting the ends of the prongs of said rows out of the plane of said strip of blanks, and forming said strip of blanks to a substantially annularly closed tube shape to convert the blanks to ring form by bending the strip of blanks transversely thereof in the opposite direction out of said plane, said bending of the strip of blanks being accomplished by advancing the same through a tapered die passage of a longitudinally movable die and imparting longitudinal reciprocating movement to the die such that the die intermittently imparts wedgingly inwardly and longitudinally acting bending forces to opposite edge portions of said strip of blanks.

16. In a method of making pronged ring fasteners of the kind shaving substantially axially extending prongs on opposite ends thereof the steps of, advancing a strip of sheet metal stock of a width substantially equal to the developed length of the fastener being produced, repeatedly shearing the stock strip transversely thereof adjacent its leading end and on an irregular line corresponding with the prong profile so as to sever from the strip by each such shearing operation a fastener blank having rows of prongs extending along opposite sides thereof, deflecting the ends of said prongs in one direction out of the plane of said blank so that the prong ends all lie on one side of said plane, maintaining the blanks in a series relation to constitute a strip of blanks and with the prongs of one blank in interfitting engagement with the prongs of an adjacent blank, curving said strip of blanks transversely to partial tube form by bending longitudinal edge portions of said strip of blanks in a direction away from said one side of said plane, said curving being accomplished by advancing the strip of blanks through a tapered die passage of a longitudinally movable die and imparting longitudinal reciprocating movement to the die such that the die intermittently imparts wedgingly inwardly and longitudinally acting bending forces to opposite edge portions of said strip of blanks, and further curling said strip by rolling to substantially annularly closed tube form.

17. In a method of making pronged annular fasteners the steps of, advancing transversely disposed prong edged fastener blanks in a longitudinally extending series and with an intermittent movement such that successive forward movements are separated by rest intervals, and curling progressively said blanks into annular fasteners by imparting wedgingly inwardly and longitudinally acting impact bending forces to opposite longitudinal edge portions of said series during the rest intervals thereof.

18. In a method of making pronged annular fasteners the steps of, providing a strip of transversely disposed prong edge fastener blanks with the prongs of adjacent blanks in meshed engagement, and curling said strip transversely thereof to substantially tubular form by repeatedly imparting wedgingly inwardly and longitudinally acting impact bending forces to opposite longitudinal edge portions of said strip.

19. In a method of making pronged annular fasteners the steps of, providing a strip of transversely disposed prong edged fastener blanks with the prongs of adjacent blanks in meshed engagement, curling said strip transversely thereof to partial tube form by repeatedly imparting wedgingly inwardly and longitudinally acting impact bending forces to opposite longitudinal edge portions of said strip, and further curling said strip by rolling to substantially annularly closed tube form.

20. In a method of making ring-shaped articles from 19 sheet metal the steps of, advancing a sheet metal stock strip longitudinally, successively shearing the stock strip transversely adjacent its leading end to provide a series of transversely disposed blanks, confining the series of blanks in a common plane with the sheared edges of adjacent blanks in abutting relation to constitute a strip of blanks, and while said strip of blanks is thus confined curling the same transversely thereof to substantially tubular form by repeatedly imparting Wedgingly inwardly and longitudinally acting impact bending forces to opposite longitudinal edge portions of said strip of blanks.

21. In a method of making ring-shaped articles from sheet metal the steps of, intermittently advancing a sheet metal stock strip longitudinally, successively shearing the stock strip transversely adjacent its leading end to provide a series of transversely disposed blanks, confining the series of blanks in a common plane with the sheared edges of adjacent blanks in abutting relation to constitute a strip of blanks, imparting an intermittent forward movement to said strip of blanks, preventing backward movement of said strip of blanks during the rest intervals of the intermittent forward movement thereof, and progressively curling said strip of blanks transversely thereof to substantially tubular form by repeatedly imparting wedgingly inwardly and longitudinally acting impact bending forces to opposite longitudinal edge portions of said strip of blanks during said rest intervals.

References Cited in the file of this patent UNITED STATES PATENTS 639,513 Bristol Dec. 19, 1899 735,936 Blakey Aug. 11, 1903 985,737 Fischer Feb. 28, 1911 1,006,838 Fischer Oct. 24, 191] 1,206,302 Cary et al Nov. 28, 1916 2,061,036 McChesney Nov. 17, 1936 2,070,766 Wilson Feb. 16, 1937 2,145,405 Schermerhorn Jan. 31, 1939 2,148,248 Swangren Feb. 21, 1939 2,177,545 Wright Oct. 24, 1939 2,222,842 Humphrey Nov. 26, 1940 2,333,997 Glans Nov. 9, 1943 2,373,530 Bertalan Apr. 10, 1945 2,417,423 Lang Mar. 18, 1947 2,444,463 Nordquist July 6, 1948 2,547,941 Heftler Apr. 10, 1951 

